1. Field of the Invention
This invention relates to an image processing method and a computer readable medium in an image processing apparatus using volume data.
2. Description of the Related Art
A design and design data of various industrial products and images for entertainment are analyzed by editing and a numeric calculation using a computer. FIG. 38 shows an example image of stress simulation by CAE (Computer aided-engineering) system. By specifying a parameter of a model on a screen with an object management GUI (Graphical User Interface), a safety factor and a deformation under stress of a component or an assembly under a structure load can be obtained.
In such CAD (Computer aided-design)/CAE (Computer aided-engineering) software, a sequence of operation can be viewed as a processing unit, and the sequence of operation that is once completed is managed as an object (for example, caption object, line object or stress simulation) and the processing unit can be reedited or redone later. The GUI for operating an individual processing unit is provided for each type of the processing unit (processing type).
On the other hand, CT (Computed Tomography) apparatus, MRI (Magnetic Resonance Imaging) apparatus, and PET (positron-emission tomography) apparatus, etc., for directly observing an internal structure of a human body, are used as a medical image processing apparatus. Medical diagnosis using tomographic images of a living body is widely conducted. Further, in recent years, as an art for visualizing a three-dimensional structure of the inside of a human body that is too complicated to understand just by using the tomographic images of the human body, for example, volume rendering has been used for medical diagnosis. In volume rendering, an image of a three-dimensional structure of an object is directly rendered from three-dimensional digital data of the object that are obtained from the CT apparatus.
As medical image processing becomes complicated and sophisticated, content of each processing unit in the medical image processing also becomes complicated and advanced. In such a medical image processing apparatus, a plurality of processes can be divided into separate processing units (such as operation and calculation), and a user operates the plurality of processes sequentially one at a time to conduct a diagnosis.
For example, while operating a certain processing unit, in a case where the user requires information other than the information being used in the processing unit under operation, or in a case where a user wants to change information in another processing unit which depends on the processing unit under operation, the processing unit under operation needs to be once completed, or editing information needs to be freed.
A possible reason why a transition to the next process cannot be made unless the processing unit under operation is once completed or unless the intermediate result is freed is that, in case of the medical image processing, the processing is complicated and a calculation amount required for one processing unit is large, or the processing units depend on each other. Furthermore, the possible reason is also that since in a medical image, data amount of volume data and the calculation amount involved therein are enormous, and the object is a complicated human body. Unlike an industrial product which can be disassembled to each component, there is a limit to disassemble a human body into each part, where each part of a human body is related to each others and each part can not be separated exactly in a image. Thus, iterative operation between several processing units is required.